Teresa Heinz Kerry is standing in the middle of a Wendy's fast-food restaurant, clutching a tiny container of chili and a bright-yellow cup of soda. She is wearing a smart brown pantsuit and a pale-pink blouse with its collar spread wide. Today is John and Elizabeth Edwards's twenty-seventh wedding anniversary, and the entire Kerry-Edwards campaign has halted its cross-country bus tour in sleepy Newburgh, New York, to let the lovebirds enjoy their traditional celebratory burgers and fries. Teresa, clearly new to Wendy's, eases her way through the crowd to join the Edwardses. She smiles gamely at her curious fellow diners. She reaches down to ruffle the dark hair of a small boy perched in a booster chair. She resembles nothing so much as a debutante at a tractor pull.

For months now the entire political world has been waiting (Republicans eagerly, Democrats anxiously) for the unscripted, uncontrollable wife of John Kerry to say or do something so outrageous that it alters the dynamics of the presidential race. Fueling expectations, every few weeks Teresa (as much of America has come to know her) lets fly another zinger—such as when she questioned the patriotism of the current President and Vice President, or when, on the eve of the Democratic National Convention, she was caught on camera telling an impertinent reporter to "shove it." In a Democratic campaign being run with the utmost caution, Teresa has been publicly deemed an "X factor" and a "loose cannon."

Barring some truly over-the-top outburst, however, Teresa's mouthiness will probably matter less than how her offbeat persona plays into voters' views about her husband. Like running mates, political spouses have meaning and impact largely in the way they reflect on the candidates themselves. Opinions vary as to how Teresa may confirm or confound the conventional wisdom about her husband. Democrats hope her spunk will combat Kerry's image as an aloof, dull-as-mud equivocator. (Surely it takes a strong, self-assured man to keep up with a spitfire like "T," as friends call her.) Republicans hope that her eye-popping wealth will help them tar Kerry as an out-of-touch elitist, and that her outspokenness will raise the question of who wears the pants in their household. (What kind of man puts up with that sort of sass anyway?) There's little question, however, that the irrepressible Teresa (pronounced Tuh-ray-za, much to the delight of Republicans) serves to highlight how very not average the Kerry family is. As one Democratic strategist put it, "My thought has always been that to the extent Kerry seems slightly odd and different from the rest of us, Teresa accentuates that."

One of the more surprising things about Teresa is how quietly she speaks. Despite her bomb-throwing reputation, her voice is low, throaty, and heavily accented in a sexy, Sophia Loren kind of way. It stays soft and measured even when she's discussing what it's like to be labeled "outspoken," "opinionated," "tough," and even "crazy" by the chattering classes.

"That's one thing about expectations for women on the campaign trail," Teresa explains to me. "If I were at a conference with colleagues and said the same things, they would not call me outspoken. They would say I was uninformed, well-informed, dumb—or whatever was appropriate. It would be contextual. But out there, the expectation is that a woman has to be adoring, silent, smiling. She is not to be measured according to who she is and what she does and what she knows." The political world has such a narrow conception of what's acceptable from the wives, she purrs.

Controversial image notwithstanding, Teresa has been a rigorous campaigner on her husband's behalf, crisscrossing the country for speeches, fundraisers, and rallies. It's a big concession from a woman accustomed to a level of privacy and privilege incompatible with campaign life—and one who has long opposed her husband's running for President. "The main reason Kerry did not run last time was that she was opposed to it," a Democrat close to the campaign told me. "She came around to it this time, and to her everlasting credit, once he got in she became an enthusiastic partner."

Though often compared to Hillary Clinton, Teresa Heinz Kerry has no political aspirations of her own and little interest in the details of her husband's race. "She's not involved in the nitty-gritty of the campaign," a former campaign staffer says. "My experience is more that she has really strong opinions on policy." This latter fact, of course, thrills Republicans, who portray Teresa as another aspiring co-President. Undeterred, she continues to share her policy views, along with her total disdain for the Bush Administration's handling of everything from global warming to stem-cell research. ("Sinful," "un-American," and "ignorant" are some of the more colorful labels she has applied to the actions of the Administration.)

On the campaign trail Teresa is generally well received by her admittedly partisan audiences. (Her frequent call for women's voices to be heard "at last and in full" is a particular favorite with the gals.) Her friends claim that the very things that make her so controversial among Beltway types—her openness, her sauciness, her international perspective—work to her advantage in talking to ordinary Americans. "She knows how to swish her hips and just take off to the music," Diana Walker, a photojournalist and a close friend of Teresa's for more than three decades, told me. Teresa's friends do acknowledge that many voters initially assume they can't relate to someone so privileged. But Allyn Stewart, a movie producer and a close friend who (like Walker) often keeps Teresa company on the campaign trail, told me that once you see how comfortable she is with people from all walks of life, "you realize what a genuine, down-to-earth person she is."

Maybe. But there remains a distinct air of otherness about Teresa—one that is especially noticeable when she's sharing the stage with the girl-next-doorish Elizabeth Edwards. Part of it is that Teresa's style is a bit too glamorous: the movie-star sunglasses, the Chanel shoes, the habit of draping her suit jacket over her shoulders like a cape. Part of it is what Walker calls her "Latin charm," which encompasses not just the accented and strangely phrased English but also a cosmopolitan world-weariness that seems not quite American. "She is so proud of her worldliness that she's made sure not to assimilate too much," a campaign intimate says. And part of it is Teresa's refusal (or inability) to observe the generally accepted standards and practices of campaign life. If her husband is delivering a speech Teresa has heard a thousand times, she does not pretend to be fascinated. If she grows tired during an event, she will lounge languidly against a nearby barricade, chin in hand. If the glare of TV lights hurts her eyes at a late-night event, she will don dark glasses. This is not to say that she makes no effort at public events. She claps. She waves. She blows kisses to the crowd and bebops to corny campaign tunes (even though she must by now want to kill herself every time she hears "Johnny Be Good"). But her efforts to play the committed political spouse are often reminiscent of watching your mom try to relate to the kids at your fifth-grade slumber party: sweet, but painfully unconvincing.

Even if Teresa were a model of wifely decorum, she would be an exotic bird in this campaign, by virtue of a personal history that's utterly foreign to most Americans. Born in 1938 to Portuguese parents living in the colony of Mozambique, Maria Teresa Thierstein Simoes-Ferreira spent her childhood climbing guava trees, swimming in crocodile-infested rivers, and accompanying her father, a successful oncologist, on visits to impoverished villages in the bush. She remembers these days as idyllic. "Think of life as a young person where cynicism is nonexistent," she tells me. "There is order and storytelling and imagination and trees for climbing, and freedom of that kind that you're surrounded by." It was a childhood filled with joy and music and love, she recalls. "And so my yardstick is pretty wholesome. My measure about what is good and important in life for all human beings is pretty simple."

But Teresa also glimpsed a grimmer side of Africa. The Mozambique of her childhood was a colonial dictatorship, and the Simoes-Ferreira family was ultimately forced to flee the country during the Marxist revolution of the mid-1970s. As a college student in Johannesburg in the late 1950s, Teresa witnessed—and marched to protest—apartheid. The political strife she saw left its mark, she says. "It taught me to take a stand."

A few years later, while studying at the University of Geneva to be an interpreter, Teresa met a young American named H. John Heinz III, of the ketchup empire, who in a classic bit of understatement told her that his family made soup for a living. The couple married in 1966, and the twenty-eight-year-old Teresa settled into a new life on the Heinz estate near Pittsburgh. She and Jack had three sons in six years, followed by three failed pregnancies. A moderate Republican, Heinz was elected to Congress in 1971 and to the Senate in 1976, but Teresa had little interest in politics and largely eschewed the campaign trail, especially when the boys were young. For twenty-five years she devoted herself to being a wife and mother.

In 1991 Teresa's domestic cocoon was shattered by a mid-air collision between a helicopter and the small plane carrying her husband around Pennsylvania on Senate business. Teresa went into a deep depression. In the wake of Jack's death she was urged by Republicans to run for his vacant Senate seat. She declined. "Teresa made a firm decision that home was where she was needed," Diana Walker told me. But as the heir to the Heinz fortune (Jack had been an only child), Teresa found herself one of the country's richest women (her worth today is estimated to be at least $500 million), with responsibility for a large charitable organization that was in considerable disarray. When a handful of charred notes on how to revitalize the foundation were found amid the wreckage of her husband's plane, Teresa decided to carry out Jack's plans herself. (First step: diversify holdings and restructure management.) Today she oversees the $1.3 billion Heinz Endowments, along with the $70 million Heinz Family Philanthropies that she founded following Jack's death. Each year the organizations distribute $60 million to programs aimed at (among other things) improving early-childhood education, expanding drug coverage for seniors, and helping cities pursue environmentally friendly development. The money often comes not only with strings attached (for instance, foundation approval for any signs placed in Pittsburgh's riverfront park) but also with tough accountability demands (in 2002 the endowments cut off grants to Pittsburgh public schools until oversight was improved). Even conservatives who grouse about the liberal advocacy work that the Heinz foundations fund don't often question Teresa's business acumen.

Teresa Heinz and John Kerry were introduced by her first husband at an Earth Day event on the Washington Mall in 1990. The two met again after Jack Heinz's death, at a 1992 environmental summit in Rio de Janeiro. As the story goes, the two fell into a long talk over dinner, much of it conducted in French. Theirs was not the starry-eyed romance of the young. (As Teresa told Elle magazine, "There was no loopety-loop.") And when courtship turned to matrimony, the couple had to contend with blending their two families (her three sons, his two daughters) as well as their firmly established lifestyles and careers. Teresa was already well aware of the downside to being a politician's wife. But John had to learn just how nasty people can be about men who marry very rich women—especially men in the expensive field of politics. (One popular joke goes, "Every time Kerry climbs into bed, he's fundraising.") Of people who question Kerry's motives for marrying her, Teresa says simply, "They're stupid."

Republicans gleefully deride Teresa's now infamous quirkiness as the arch, imperious manner of a super-rich cultural elitist. The underlying political message: A presidential candidate married to this woman cannot possibly relate to ordinary Americans. Contributing to this slant is Teresa's unfortunate tendency to say and do things highlighting the fact that neither she nor her husband hails from anywhere near Middle America—for instance, she opened her convention speech in five languages, and she has compared Kerry to a fine wine: "You know, it takes time to mature, and then it gets really good and you can sip it."

But even though she's taken some hard hits, Teresa is not overly concerned with toning down her style or avoiding controversy. (During remarks she made at a Milwaukee campaign stop, a group of pro-Bush hecklers began chanting, "Four more years!" She promptly fired back, "They want four more years of hell!") "Teresa is very proud of being headstrong and candid—and powerful," a friend of Kerry's told me. (The same goes for her cherished "Europeanness," he added.) Indeed, Teresa's friends are outraged at the idea that she would even consider trimming her sails to fit a more traditional image of a candidate's wife. "Teresa Heinz Kerry is honest and she is straightforward and she is not afraid to be herself," Diana Walker says, her voice rising. "Why is that criticized? It should be enjoyed. It should be considered a breath of fresh air in politics today." Teresa herself is more philosophical. "People will write and [say] whatever about me for different motives—or for no motive at all," she says in that soft, drowsy voice. "I can't control that. I can only control what I say and what I do."